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Sunday, January 11, 2009

PostHeaderIcon What is PHP?

10:54 AM | Posted by Hari Kiran | Edit Post


PHP (Recursive acronym for "PHP: Hypertext Preprocessor") is a widely-used Open Source general-purpose scripting language that is especially suited for Web development and can be embedded into HTML.

Simple answer, but what does that mean? An example:


Introductory Example

<HTML>
Example
<body>
This is normal text (HTML)

<?php
echo "Hi: PHP Line";
?>

</body>
</HTML>


Notice how this is different from a script written in other languages like Perl or C -- instead of writing a program with lots of commands to output HTML, you write an HTML script with some embedded code to do something (in this case, output some text). The PHP code is enclosed in special start and end tags that allow you to jump into and out of "PHP mode".

What distinguishes PHP from something like client-side JavaScript is that the code is executed on the server. If you were to have a script similar to the above on your server, the client would receive the results of running that script, with no way of determining what the underlying code may be. You can even configure your web server to process all your HTML files with PHP, and then there's really no way that users can tell what you have up your sleeve.

The best things in using PHP are that it is extremely simple for a newcomer, but offers many advanced features for a professional programmer. Don't be afraid reading the long list of PHP's features. You can jump in, in a short time, and start writing simple scripts in a few hours.

Although PHP's development is focused on server-side scripting, you can do much more with it.

Few Points to ponder:


  • PHP Files are generally saved with extension .php

  • PHP code must be embedded in between start and end tags

  • Mainly two types of tags available for PHP they are
    1."<?" and "?>" - short hand tag
    2."<?php" and "?>" normal tag

    • * "<%" and "%>" - general script tags(ASP, JSP etc..) can be enabled by configuring in web server.
  • In PHP all the variables must start with a "$" symbol.

  • If $ symbol is missed in front of a variable, it would be treated as dirty string.(T_String).



In the next section we will know about Variables and Data Types
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